Higher performance electronic components are increasingly used in assemblies for automation technology thus necessitating measures for dissipating the heat from the assemblies. For this, it is usual to employ heat sinks in these assemblies, in particular because fans for heat dissipation are not desired in automation technology.
Known from the Siemens Catalog ST 70, Edition 2007, pages 5/2 and 5/112 is an automation device comprising a plurality of assemblies and a mounting rack. The mounting rack is provided to accommodate the assemblies and to supply them with an operating voltage, wherein the assemblies may be plugged into slots in a rear panel bus by means of which the assemblies are connected to each other. Each slot in the mounting rack has on one edge three spring contacts arranged in parallel and provided with a ground potential which are electrically connected to a connector of a plugged-in assembly. Due to the ageing of the spring contacts and the associated deterioration in the elasticity of the spring contacts or due to contamination of the spring contacts, there is an increase in the contact or transfer resistance between the spring contacts and the corresponding connector of the respective plugged-in assembly. This results in an increase in the electrical power loss at the contact point and in addition the thermal power loss from the assembly is only poorly dissipated by the rear panel bus resulting in an increase in the temperature in the assembly. If a critical temperature is reached in the assembly, its operation can be disrupted and this has a detrimental impact on the technical process to be controlled.